Internal broaching machine



8' 1955 v. J. BRYANT ETAL 3,

INTERNAL BROACHING MACHINE Filed June 1, 1962 3 Sheets-Sheet l I NVEN TORS 0 Mc ma 7 Bey/9N7 Aug. 10, 1965 v. J. BRYANT ETAL 3,199,409

INTERNAL BROACHING MACHINE Filed June 1, 1962 3 Sheets-Sheet 2 C0f/7/V6 5720/5 Pin/0v SIMI I 1 I I r0 VICTOR 7 fi l y q EON/9L0 L. Aka/l BHLD g 1955 v. J. BRYANT ETAL INTERNAL BROACHING MACHINE S Sheets-Sheet 5 Filed June 1, 1962 I v4 re INVENTORS Wave .7 BRYAN 7. EON/2L0 L QRCH/Efll. a.

United States Patent 3,199,409 INTERNAL BRQACHING MACHINE Victor James Bryant, 132 Westfield Ave., Watford, England, and Ronald Leonard Archibald, 291 Park Ave, Bnshey, England Filed June 1, 1962, Ser. No. 1%,415 3 Claims. (Cl. 90-96) This invention relates to internal broaching machines and in particular to the puller mechanism by which the broach is drawn through the work.

According to the invention, there is provided an internal broaching machine having a broach puller mechanism which comprises a sleeve provided with two internal cam surfaces and slidable on a puller body, the first cam surface being effective to engage pulling studs in the body in a groove in an inserted broach and the other cam surface being eifective to engage locating studs in the body against corresponding flats in the broach so that the broach is locked in an angular direction.

According to an important feature of the invention, automatic means is incorporated for releasing the broach from the puller mechanism at the end of the cutting stroke.

An embodiment of the invention will now be described with reference to the accompanying drawing in which:

FIG. 1 is an end elevation of the puller mechanism of an internal broaching machine;

FIG. 2 is a section on the line IIII of FIG. 1, showing the mechanism in broach-engaging condition;

FIG. 3 is a side elevation of the mechanism of FIGS. 1 and 2;

FIG. 4 is a view similar to FIG. 3 but showing the mechanism in broach-releasing condition at the end of the return stroke;

FIG. 5 is a sectional elevation similar to FIG. 2 but with the mechanism in a broach-releasing condition, and

FIG. 6 is a purely-diagrammatic sketch of the operation of the mechanism in the broaching machine, the workpiece being omitted for clarity.

The main construction and operation of the puller mechanism is similar to existing practice in that a springloaded sliding sleeve 1 is fitted with an internal cam surface 2 (FIGS. 2 and 5) adapted to produce inward radial movement of a plurality of pulling studs 3 in a puller body 4 which the sleeve surrounds. These studs engage in a circumferential groove 5 in the broach 6 and lock it to the puller, outward movement of the studs being prevented by the interior plane surface 7 of the sleeve beyond the cam surface 2. According to the invention, the outer end of the puller body 4 has two further radially-movable studs 8 whose outer ends are adapted to co-operate with a further cam surface 9 on the sleeve 1. The inner ends of these two locating studs are flat and are positioned to engage two diametrically opposed flats 10 accurately machined for the purpose in the broach end. As the sleeve slides on the puller body under the action of the spring 11 and causes the puller studs 3 to engage in the groove 5 in the broach, the second cam surface 9 forces in the two locating studs 8 against the flats 10 and ensures that the broach is accurately located angularly. It is to be noted that sufiicient sliding movement is permitted to the sleeve to ensure that the locating studs 8 are locked in their flats.

The means for releasing the broach from the puller by sliding back the sleeve is in the form of a double-armed, U-shaped lever 12 pivoted on extensions 13 of the puller draw head 14 a short way up each arm. The two free ends of the arms are provided with rollers 15 engaging in grooves 16 in the sleeve 1 and a third roller 17 (FIGS. 1, 3 and 4) is journalled in a bracket 18 projecting from the bottom of the central portion of the U. At the end of 3,199,4fi9 Patented Aug. 10, 1965 the cutting stroke of the broach (to the left of FIG. 6), a cam 19 on the frame of the machine is operative on the roller 17 to swing the U-lever 12 about its pivots and retract the sleeve against the spring 11. Provision is, of course, made to support the broach when thus released and this provision may conveniently take the form of a support roller 20 raised from the bed of the machine at the appropriate time. After release, the broach can be lifted or traversed out of operative position and the puller drawhead returned to its initial position (to the right of FIG. 6). Since the broach itself is not returned, a second broach can be pre-positioned ready to be engaged by the puller as soon as the latter has been returned. In order to allow the second broach to be gripped by the puller at this point, two stops 21 are provided on the face plate 22 which act on ramps 23 on the arms of the U lever 12 just above its pivots with sufficient leverage to slide the sleeve fully back with a relatively small movement of the puller to the position shown in FIGS. 4 and 5.

It should be understood that the foregoing description is for the purpose of illustration only and that the invention includes all modifications and equivalents which fall within the scope of the claims.

We claim:

1. The combination with a broach puller having a puller body containing an opening for receiving the end of a broach, and a broach having a circular locking groove and a fiat positioning land located at a predetermined angular position relative to the axis of the broach, said body containing axially spaced and circumferentially spaced openings for receiving, respectively, locking pins and positioning pins; of pins situated in said openings with their ends projecting from the outer side of said puller body, and a cam sleeve slidable on said puller body, said sleeve containing internal recesses opposite the outer ends of the pins within which the pins are adapted to be received for clearance of their inner ends from engagement with the broach, and adjacent inclined surfaces constituting cams engageable With the outer ends of the pins, by axial movement of the sleeve, to press the inner ends of the pins into engagement with the locking groove and the positioning land.

2. Broaching apparatus comprising a broach puller supported for linear movement relative to a Work support for movement of the broach relative to the work on the support, said puller comprising a puller body containing an axial hole for receiving the end of the broach having a circular locking groove and a flat positioning land for angular orientation of the broach about its longitudinal axis relative to the work on the work support, said puller body containing circumferentially spaced openings for receiving locking and positioning pins, locking and positioning pins situated in said openings with their outer ends projecting from said puller body, a cam sleeve mounted on said puller body over the outer ends of said pins, operable, by axial movement thereon, to press the pins into the locking groove and against the positioning land, yieldable means normally holding the cam sleeve in looking position, and means supported by the sleeve and movable therewith having a part engageable, as the puller nears the end of the cutting stroke, to displace the sleeve in a direction to compress the spring, said last-named means comprising a lever pivotally mounted on said puller body on an axis transverse to the path of movement, a roller mounted on the lever for movement linearly with said puller body, and a cam element located adjacent the end of the cutting stroke in the path of movement of the roller operable, by interception of said roller, to displace the lever in a direction to compress the spring.

3. Broaching apparatus comprising a broach puller supported for linear movement relative to a work support for movement of the breach relative to the Work on the support, said puller comprising a puller body containing an axial hole for receiving the end of the broach having a circular locking groove and fiat positioning land for angular orientation of the broach about its longitudinal axis relative to the work on the Work support, said puller body containing circumferentially spaced openings for receiving locking and positioning pins, locking and positioning pins situated in said openings with their outer ends projecting from said puller body, a cam sleeve mounted on said puller body over the outer ends of said pins, operable, by axial movement thereon, to press the pins into the locking groove and against the positioning land, yieldable means normally holding the cam sleeve in locking position, and means supported by the sleeve and moveable therewith having a part engageable, as the puller nears the end of the cutting stroke, to displace the sleeve in a direction to compress the spring, said lastnamed means comprising a U-shapedlever, means pivotally mounting the arms of the lever intermediate their ends on said puller body for rotation of the lever about an axis transverse to said puller body and its path of movement, said puller body containing grooves perpendicular to the path of movement, rollers at the ends of References Cited by the Examiner UNITED STATES PATENTS 823,833 6/06 Webb 9096 2,135,861 11/38 Thompson 90-93 2,408,521 10/46 La Pointe 9070 2,420,877 5/47 Geren 90-96 W lLLIAM W. DWYER, JR., Primary Examiner. 

1. THE COMBINATION WITH A BROACH PULLER HAVING A PULLER BODY CONTAINING AN OPENING FOR RECEIVING THE END OF A BROACH, AND A BROACH HAVING A CIRCULAR LOCKING GROOVE AND A FLAT POSITIONING LAND LOCATED AT A PREDETERMINED ANGULAR POSITION RELATIVE TO THE AXIS OF THE BRAOCH, SAID BODY CONTAINING AXIALLY SPACED AND CIRCUMFERENTIALLY SPACED OPENINGS FOR RECEIVING, RESPECTIVELY, LOCKING PINS AND POSITIONING PINS; OF PINS SITUATED IN SAID OPENINGS WITH THEIR ENDS PROJECTING FROM THE OUTER SIDE OF SAID PULLER BODY, AND A CAM SLEEVE SLIDABLE ON SAID PULLER BODY, SAID SLEEVE CONTAINING INTERNAL RECESSES OPPOSITE THE OUTER ENDS OF THE PINS WITHIN WHICH THE PINS ARE ADAPTED TO BE RECEIVED FOR CLEARANCE OF THEIR INNER ENDS FROM ENGAGEMENT WITH THE BROACH, AND ADJACENT INCLINED 